The invention is directed at a thermostatically controlled mixing valve. Mixing valves of this type have one inlet for cold water and another inlet for hot water. The mixing ratio between the hot water and the cold water is obtained by a valve body in the form of a control bush placed in a control sleeve. The mixing water temperature is exposed to an expansion element moved axially in the control bush. During movement it changes the ratio of hot to cold water.
As a result of the space available and the standard temperatures, as well as the material used for the expansion element, the width of the slot between the control bush and the associated valve seat is approximately 0.4 to 0.8 mm. Thus, if a specific flow cross-section is required, this leads to a relatively large control bush diameter derived therefrom.
The problem of the invention is to provide a thermostatically controlled mixing valve, which permits large flow cross-sections of the control openings with a very limited space requirement.
Thus, the mixing valve proposed by the invention uses a valve body having, at least on one side, at least two control openings for the inflowing water. On the other side, i.e. the side with the higher or lower temperature, the invention provides for at least one control opening, but preferably also two control openings.
The measures of the invention make it possible to in each case open or close two control openings with the same stroke or travel. This makes it possible to double the flow cross-section of the control openings in the opened state. When there are more than two control openings on each side, the flow cross-section can be further increased. This increase in the flow cross-section for an unchanged stroke quantity can be utilized for reducing the valve body diameter and therefore the fitting size. It can be adequate for there to be two control openings only on one side of the valve, e.g. the hot water side. However, it is particularly favourable if there are at least two control openings on both sides of the valve.
According to a further development of the invention, each control opening is formed by a movable portion of the valve body and a non-movable part of the mixing valve, particularly by part of the casing.
According to a further development of the invention, at least one control opening is formed between a slot of the valve body and an edge of the mixing valve casing. Through the displacement of the slot with respect to the casing edge, it is possible to increase or decrease the flow cross-section of the control openings.
It is also possible and is proposed by the invention that at least one control opening is formed between two control faces, the valve body movement direction being roughly perpendicular to at least one control face.
According to another further development of the invention, on the casing is placed a valve seat, which together with the valve body forms a control opening.
Also in the case of the thermostatically controlled mixing valve proposed by the invention, a control bush can be used as the valve body.
According to the invention, at least one end face of the valve body cooperates with a control face forming a valve seat for forming a control opening.
It is possible for at least two control openings to be spaced from one another in the valve body movement direction. Particularly if the valve body is moved axially, this ensures that the inflowing water can penetrate over a relatively large area in the axial direction.
According to a further development of the invention, at least one control face has an elastic surface. As the control openings are closed simultaneously, this can be used for compensating tolerances resulting from manufacture. The elastic surface can be formed by an insert or support of an elastic material, particularly an elastomeric material. At least one seat can be sprung.